isa: Use a bus_child_deleted method to free ivars for children

sys/isa/isa_common.c

  */
 
 #include <stddef.h>
 #include <stdlib.h>
 
 #ifdef  I_AM_BSEARCH_B
 #include "block_abi.h"
 #define COMPAR(x,y)     CALL_BLOCK(compar, x, y)
+typedef DECLARE_BLOCK(int, compar_block, const void *, const void *);
 #else
 #define COMPAR(x,y)     compar(x, y)
 #endif
 
 /*
  * Perform a binary search.
  *
  * The code below is a bit sneaky.  After a comparison fails, we
  * divide the work in half by moving either left or right. If lim
  * is odd, moving left simply involves halving lim: e.g., when lim
  * is 5 we look at item 2, so we change lim to 2 so that we will
  * look at items 0 & 1.  If lim is even, the same applies.  If lim
  * is odd, moving right again involves halving lim, this time moving
  * the base up one item past p: e.g., when lim is 5 we change base
  * to item 3 and make lim 2 so that we will look at items 3 and 4.
  * If lim is even, however, we have to shrink it by one before
  * halving: e.g., when lim is 4, we still looked at item 2, so we
  * have to make lim 3, then halve, obtaining 1, so that we will only
  * look at item 3.
  */
 #ifdef I_AM_BSEARCH_B
 void *
 bsearch_b(const void *key, const void *base0, size_t nmemb, size_t size,
-    DECLARE_BLOCK(int, compar, const void *, const void *))
+    compar_block compar)
 #else
 void *
 bsearch(const void *key, const void *base0, size_t nmemb, size_t size,
     int (*compar)(const void *, const void *))
 #endif
 {
         const char *base = base0;
         size_t lim;